Coke oven



W. H. PAVITT Sept. 11, 1934.

COKE OVEN Filed June 4. 1932 2 Sheets-Sheet 1 INVENTOR. WILLIAM H. PA VITT Patented Sept. 11, 1934 hire STATES ersnr osric COKE OVEN EVilliam Hesser Pavitt, Bronxville, N. Y. Application June 4, 1932, Serial No. 615,446

Claims.

My present invention relates to coke ovens having vertical heating flues as do the most usual present day forms of the regenerative by product type of coke oven. In such coke ovens the coking I 5 chambers are deep horizontally elongated chamby reducing the coking time, i. e. the time required for properly coking each charge of coal put into an individual coking chamber. In general, a reduction in the coking time requires an increase in the rate at which heat is conducted per unit of flow area through the brickwork between the flue space in a heating wall and the coking charge in the coking chamber or chambers alongside that wall. The length of the coking time is dependent on the distribution of the heat flow into the charge from the adjacent heating walls.

With ideal heat distribution, each unit of area of the side of a coking charge would receive heat at the rate required to coke the section of the charge in horizontal alignment with said area unit at the same time rate, as each other section of the charge is coked. Such ideally uniform heat distribution is never fully attainable in practice, and its lack is more or less fully corrected for by continuing the coking operation to subject the charge to a sort of final heat soaking action, during which'the previously under coked sections of the charge receive the additional heat necessary 40 to sufliciently complete their coking. In this final heat soaking action, the sections of the charge in which the coking action is being completed receive some heat by conduction from adjacent and'more completely coked sections of the charge so that the temperatures and degrees of coking of thedifferent sections of the charge are more or less thoroughly equalized. Other things being equal, the better the heat distribution the smaller is the heat soaking period required, and thesh'orter the total coking period. I

Suitable heat distribution is desirable not only because of its direct effect in shortening the. coking perfod and in avoiding or minimizing the overheating of sections of the charge, but also because it tends to reduce the maximum oven brick-.-

work temperatures. With improper heat distribution some portions of the heating walls are necessarily heated to higher temperatures than are other portions, and in the effort to obtain the desired rap d heating required for a short coking period, the more highly heated portions of the walls are frequently heated to, or dangerously near to temperatures high enough to injure such wall portions.

In the operation of vertical flue coke ovens, when heated by the combustion of a relatively rich'fuel gassuch as coke oven-gas at the rate required for the relatively short coking periods common with modern commercial practice, if-the combustion of thefuel gas in each vertical fine is initiated at or closely adjacent the level of the bottoms of the flues and the adjacent coking chambers as was formerly the universal practice, Y

the lower portion of the charge in each coking chamber invariably receives more heat than is received by the upper portion of the charge. This results in what is commonly referred to as hot bottoms, and has led to some use of high and low burner arrangements, i. e. arrangements by which combustion is initiated in some of the vertical flues in each heating wall at the usual level, i. e. at or adjacent the bottom level of the coking chambers, and is initiated'in other vertical flues at higher levels. For example in some commercial ovens, combustion is initiated at the usual level in every alternate flue of a heating wall, while in the intervening flues, combustion is initiated at a level above the usual level by a distance equal to a fourth or so of the vertical flue length. Usually, though not necessarily all the low burners are located at one level, and all the higher burners at a different level.

The use of previously known high and low burner'arrangement has'been found praptically efiective in avoiding hot bottoms, but has given rise to a disadvantageous tendency to under heating of the sections of the charge immediately ad ing, the tendency to unequal heating directly due to initiation of combustion only at levels substantially above that of the bottoms of the charges in such of the vertical flues as contain high burners. I accomplish this result by the use of high and low burners in flues especially shaped to avoid the tendency to under heating of the portions of the charge immediately adjacent the portions of the high burner flues which are below the levels'of the burners in those fines.

To this end I make the width, or horizontal flue dimension parallel to the length of the heating walls, of each flue containing a low burner, greater in the lower portion of the flue than in the lower portion of an adjacent flue containing a high burner, and preferably make the lower width of the upper portion of each fluecontaining a low burner less than the width of the upper por tion of an adjacent flue containing a high burner. In preferred embodiments of the invention each of the vertical flues is tapered from top to bottom, the tapers of the flues containing the high burners being the reverse of that of the flue-s containing the low burners. By proceeding in the manner described, the cross section of the path of flow by heat conduction through the heating wall is increased and the resistance of said path to heat flow is reduced from the bot torn to the top of the flue for each flue containing-a low burner and from the top to the bottom ofe'ach flue containing a high burner;

The various features of novelty which charactjerize my invention are pointed out with'partieularity in the claims annexed to and forming apart of this specification, For a better under-.- standing of the invention, however, and the ad-' vantages'possessed by it reference should be had to the accompanying drawings and descriptive matter in which I have illustrated and described a refe ed b imen o h inv ti n.

Of he drawin s:

Fig, 1 is a somewhat diagrammatic transverse sectional elevation of a coke oven battery, the section being talgen on the line 1-1 of Fig. 2;

Fig. 2 is a partial section taken on the line 22 of Fi r Fig. 3 is a partial horizontal section taken on the line 3'-,.-3 of Fig. 1; V l V v Fig. i is a view taken similarly to Fig. 1 illustrating a modified embodiment of the present -in. ven n a Fig 5 is a partial section on the line 55 of Figni, ,7 n 1-3 of the drawings, I have illustrated a preferred embodiment ofv my invention incor-, porated in a so-called underflred oven of ,well known type with vertii alhorizontally elongated coking chambers A and with a vertical horizontally elongated heating wall B between each adjacent pair of chambers A. "Each heating wall 13 is formed with vertical'heatingflues C and CA arranged in a row extending from one end of the'wall to the other, the flues C alternating with the flues CA. Each flue C is connected at its upper end to the upper end or" an adjacent flue CA above the flue division wall D between the two flues', so that each pair of flues so connected constitute' a so-called twin or hairpin flue. The different hairpin or twin flues in each. heating wall 1 are separated from one another by flue division the purposes of the present invention, in the walls d. 1

Beneath each heating wall is a corresponding pillar wall E. Regenerators F are located in the spaces between thepillar walls. The flues C and CA are connected at their lowerends by channels C and C respectively, to adjacent regenerators, the flues C and CA of each pair constituting a twin or hairpin flue being connected to different regenerators. In the particular arrangement shown in Figs. 1-3 there are three side by side regenerators between each pair of pillar walls and each of the flues C and CA is connected by two channels C and C respectively, to two regenerators, 'to facilitate the use of a lean fuel gas which requires preheating, but the present invention is not concerned with the details .of that arrangement. 7

' Each flue C is provided with a high burner or fuel gas inlet H opening to the flue at a level suitably above the bottom of the flue, and as shown, at a distance above that level, and the approximately similar level of the bottoms of the chambers A, equal to one-fourth or so of the vertical flue length. Each flue CA is provided with a low burner or fuel'gas inlet 71. opening to the flue at about the level of the bottoms of the coking chambers. In the type of underflred oven illustrated, the fuel gas inlet passages are in the form of vertical channels in the oven masonry extending downward through the corresponding pillar walls and connected, ordinarily through separate regulating valves, to gas distribution piping I located in the space formed in the foundation subesti'ucture on which the oven structure proper including the pillar walls and regenera tors is shown as supported.

. In heating the oven shown in Figs. 143 by the a combustion of rich fuel gas supplied alternately to the burner inlets .I-I and'h, each high burner flue C receives fuel gas through its inlet-H and receives preheated air for the combustion of the gas from the regenerators to which the lower end of the flue is connected during certain periods of operation, inwhich that flue serves as an up flow flue in which combustion is initiated. The 1 15 gases then issuing from the upper end of the flue pass downward through the connected flue CA, which then serves as a downflow flue "delivering the gases to the regenerators connected to the lower end of thelast mentionedflue. During 110 other periods of operation alternating with those first mentioned, the flow through the flues and regen'erators is reversed, so that the flue CA previously serving as a downflow flue becomesan upflow flue in which the combustion of fuel supplied thereto by the corresponding inlet, is initiated and which delivers gases to the-connected flue C which then serves as a downflcw flue. No necessity exists for describing the valves and other-mechanismwhereby the flow of air, fuel gas and products of combustion through the different vertical fines and regenerators is directed and regulated, as mechanism for the purpose is well known and its details form no part of the present invention.

Insofar as the structure shown in Figs. 1-3 has been described, it is merely a typical instance of the prior art constructions with which the present invention may be employed. In coke ovens of the generalform illustrated in Figs. 13, as heretofore constructed, the flue division walls D and d haveoi'dinarily been vertical so that from top to bottom each of the fines C and CA is uniform in width orhorizontal extent in the direction of the length of the heating walls. For

forms thereof shown in Figs. 1-3 the flue division Walls Dare inclined to'th'e veitica'l, the fiue'division wallsd being vertical as usual, so that each high burnenflue 'C is appreciably wider at its upper end than at its lower end, and so that each low burner flue CA is appreciably wider at its lower end than at its upper end. In practice, and as shown, the widths of the upper and lower ends of each flue C may be approximately equal to the widths of the lower and upper ends, respectively, of each flue CA.

With the fines C and CA so shaped, the portions of the charge immediately adjacent the portions of the high burner flues C whichare below the high burners therein, are narrower than the portions of the charge immediately adjacent the lower portions of the low burner flues CA. In consequence, the path of flow for heat conducted into the charge through the heating wall masonry from the lower portion of each low burner flue CA is relatively large in cross section and of correspondingly low resistance to heat flow. In consequence, the lower portions of the fines CA may readily supply all of the heat required not only by the portions of the charge immediately adjacent those flues, but also by the portions of the charge immediately adjacent the lower portions of the flues C. While the heat inflow into the last mentioned portions of the charge, particularly in the initial stages of the coking operation, will not be as rapid as into the portions of the charge immediately adjacent the lower ends of the flues C, the difference in the rate of heat flow is relatively small and of relatively minor practical importance.

With the described arrangement the amount of heat supplied by the lower portion of each low burner flue CA is relatively large in comparison with the amount supplied by the upper portion of that flue. This is compensated for more or less by the increased widths of the upper portions of the fines C which give up relatively more of their heat to the charge at the upper ends of those flues than at lower portions of the flues.

My invention is obviously not limited to use in a coke oven of the particular form shown in Figs. 1S, but is equally well adapted for use in any other form of vertical flue coke oven now in use with but little change in form. In the use of the present invention in coke ovens in which the vertical fiues in each heating wall are connected at their upper ends in groups to upper horizontal channels in end to end relation with one another, as illustrated, for example, in the Becker Patent 1,376,546, granted April 12, 1921, or are all connected to a common upper horizon tal. channel J as shown in Figs. 4 and 5, the alterflue division walls DA and DB may well be alike, except that the walls DA are all inclined in one direction to the vertical, while thealternate walls DB are all inclined to the vertical in the opposite direction. With the oven formed as shown in Figs. 4 and 5 all of the high burner fiues C and low burner flues CA adjacent one end of any one heating wall, and constituting half, or approximately half, of the flues in that wall, serve as upfiow flues in which combustion is initiated, during one operating condition, and as downflow fines when the flow is reversed, while the remain ing iiues C and CA in the wall serve as downflow flues in the one condition of operation, and as upflow flues in which combustionis initiated when the flow is reversed. The oven structure shown in Fig. 4 includes regenerators F in end to end pairs, the regenerators of each pair being separated by a division wall F, to which the lower ends of the fines C and CA are connected, and includes high and low burner fuel gas supply connections generally like those shown in Figs. 1-3.

While in any particular coke oven structure all of ti e high burners may be located at one level and all of the low' burner-sat another level'in many cases, it will be apparent to those skilled in wall should have one, and one only, high burner,

and that each of the remaining fiues in thewall should have one, and one only, low burner. For eXamplefas-shown in Figs.4 and 5, the two end flu-es CA of each wall may well be made slightly wider than the other low burner flues, and may each be provided above with a high burner inlet H and a low burner inlet h. The provision of the ave-burner inlets in each of the end fines CA insures an adequate supply of heat to the end flues'to compensate for the loss of heat by radiation at the adjacent horizontal ends of the coking charges. I

While both embodiments of my invention illustrated in the drawings hereof are coke ovens of the underfired type, those skilled in the art will understand that the invention is equally applicable to coke ovens in which the fuel gas is supplied through horizontal channels in the pillar walls beneath the heating walls as is customary practice in this country. For example, the particular arrangement of high and low burners and flue division walls employed in the under-fired oven illustrated in Figs. 1-3 hereof, might be equally well employed in the Wilputte type of twin flue oven illustrated in the Wilputte Patent 1,360,609, granted November 30, 1920.

While in accordance with the provisions of the statutes, I have illustrated and described the best form of embodiment of my invention now known to me, it will be apparent to those skilled in the art that changes may be made in the form of the apparatus disclosed without departing from the spirit of my invention as set forth in the appended claims and that in some cases certain features of my invention may be used to advantage without a corresponding use of other features.

Having now described my invention what I claim as new and desire to secure by Letters Patent, is:

1. In a coke oven a vertical heating wall there for having a row of side by side vertical fines, each of the alternate fiues having a burner therein adjacent the bottom thereof and each of the intermediate fiues having a burner therein a substantial distance above the bottom thereof, each of the alternate flues being of greater width, along the heating wall, adjacent the lower end thereof than at the upper end thereof and each of the intermediate flues being of greater width. "1 along the heating wall, at the upper end thereof than adjacent the lower end thereof.

2. In a coke oven a vertical heating wall therefor having a row of side by side vertical combustion flues, one flue of each of pairs of side by side flues having a burner therein adjacent the bottom thereof, and the second flue of each such pair having a burner therein a substantial distance above the bottom thereof, said one flue of each such pair being of greater width, along the heating wall, adjacent the lower end thereof than at the upper end thereof and said second flue of each such pair being of greater width,'alongthe heating wall, at the upper end thereof'than adlament the lower end thereof.

3. In a coke oven a verticalheating Wall therefor having a row of. side by side vertical combustion flues, said flues being connected in pairs at their upper ends, one flue of each pair having a burner therein adjacent the bottom thereof, and the second flue of each pair having a burner therein a substantial distance above the bottom thereof, the said one flue of each pair being of greater width, along the heating wall, adjacent the lower end thereof than at the upper end thereof, and said second flue of each pair being of greater width, along the heating wall, at the upper end thereof than adjacent the lower end thereof.

4. In a coke oven a vertical heating wall therefor having a row of side by side vertical flues and a division wall between each two adjacent fines of the row, each of the alternate flues having a burner therein adjacent the bottom thereof, and each of the intermediate fiues having a burner therein a substantial distance above the bottom thereof, the division walls being inclined so as to make each of the alternate flues of greater width, along the heating wall; adjacent the lower end, thereof than at the upper end thereof, and each of the intermediate flues of greater width, along the heating wall, at the upper end thereof than adjacent the lower end thereof.

5. In a coke oven a vertical heating wall therefor having a row of side by side vertical fines and a, division wall between each two adjacent flues of the row, each of'the alternate flues having a burner therein adjacent the bottom thereof, and each of the intermediate flues having a burner therein a substantial distance above the bottom thereof, the adjacent division-walls being oppositely inclined so as to make eachof said alternate flues'of greater width, along the heating wall, adjacent'thelower end thereof than at theYupper-iend thereof and each of the intermediate flues of greater width, along the heating Wall, at the upper end thereof than adjacent the lower end thereof.

WILLIAM HESSER PAVITT. 

